Migration resistant packing material



Julyl, 1962 A. GRAHAM 3,047,136

MIGRATION RESISTANT PACKING MATERIAL Filed Oct. 28. 1958 F i Q 3 INVENToR. Arthur Graham M 9&9

Attorneys lb Patented July 31, 1962 3,047,136 MIGRAHDN RESISTANT PACKING MATE Arthur Graham, 1548 Edgewood, Palo Alto, Calif. Filed Get. 2S, 1958, Ser. No. 776,031 6 Claims. (Cl. 286-46) This invention relates generally to packing materials, such as are used in the storage and shipment of frangible items of merchandise, and more particularly relates to a packing material of the type disclosed in copending application Serial No. 761,260, filed September 15, 1958.

ln general, it is an object of the invention to improve upon such packing material, and particularly with respect to improvements in construction which will prevent migration of a packed item through the packing material.

It is another object of the invention to provide a packing material of this type that is particularly useful with delicate, fragile but relatively heavy items of merchandise, whereby a difficult breakage problem is -virtually eliminated.

Another object of the invention is to provide a packing material of such type that is readily adaptable to machinetype, production-line methods of manufacture.

Additional objects and advantages of the invention will appear from the following description and from the drawing in which:

FIGURE 1 is a view in perspective of a quantity of packing material embodying the invention;

FIGURE 2 is a like view illustrating a carton packing operation in accordance with the invention;

FIGURE 3 is a vertical section showing the use of the packing material of FlGURE l in a carton that has been sealed for shipment or storage; and

FIGURE 4 is a like view showing the manner in which the packing material serves to prevent migration of the packed item while simultaneously absorbing impacts and shock.

One diihculty in the handling or shipping of extremely delicate but relatively heavy equipment, such as electronic or optical equipment, is migration of the item through the packing material due to continuous vibration or handling. For example, in shipments in a van or rail car, migration of the packed item will frequently continue until contact is made with a wall of the shipping carton 4 and breakage occurs. Breakage from this and other normal causes customarily runs as high as fifteen percent, and may be considerably higher if prolonged shipment or handling is involved.

In accordance with the present invention, the problem of breakage due to migration and other similar causes is solved by the use of a multiplicity of elongated strings of hollow crushable cylinders, massed Within and around the packed item. Specically, I have found that the use of elongated hollow tubes composed of a plurality of connected articulated segments is highly effective in preventing shifting or displacement of the packed item, and serves to virtually eliminate breakage or damage. By way of illustration, ordinary drinking straws of sized paper or plastic material which have been partially cut through at intervals of, say, 1A to 2 inches, possess a combination of qualities that make them ideal for use as a packing material. They possess an usual resilience and crushability which serve to absorb impact or shock, While at the same time providing a plurality of spaced wedgeshaped openings particularly adapted to interlocking with other strings of the packing material to prevent migration. I have also found that this resistance to migration can be enhanced by the application of a resilient or rubbery exterior surface to the strings of packing material. Such surface acts to reduce the sliding characteristic and to supance.

2 plement the interlocking effect provided by the wedgeshaped openings.

Referring to the drawing, FIGURE/1 illustrates a quantity of strings 10 of the packing material, each composed of a plurality of individual tubular segments 12 joined along one edge by a connecting portion 14. In a preferred form, the strings 10` are fabricated from ordinary drinking straws which have been sliced or partially cut at intervals to leave a portion of the original tubular surface as the connecting portions 14. These connecting portions permit a degree of bending or articulation of the strings toprovide Wedge-shaped openings 16 along the length of the strings 10. In use, these Wedge-shaped openings cause a certain interlocking or wedging of the strings together so that a mass 20 of the strings has a certain cohesiveness, as suggested in FIGURES l and 2.

The hollow tubular segments 12 of the strings impart a high degree of initial stiffness to the packing material which tends to support the weight of an item packed within the packing material. They also impart a crushability or shock-absorbing characteristic to the packing mass which provides a high degree of shock or impact resist- This effect is represented in FIGURE 3, which illustrates the packing of a heavy piece of electronic equipment such as a delicate klystron tube 22. Such tubes normally include heavy magnets or similar components, and the area 24 indicate-s a certain amount of compacting or deformation of the packing mass to absorb the considerable weight of the tube. AThis compacting is due to a partial crushing of the individual tubular segments 12. Further compacting or crushing is resisted, however, by interlocking of the individual strings of material and by the inherent stiffness of the mass 2d.

Preferably, the strings 10 are fabricated from conventional, spirally-Wound and glued straw stock, such as common drinking straws. Such material is readily available and offers manufacturing convenience. However, the strings 10 may be conveniently fabricated of various materials. By way of illustration, the strings can be cut from continuously extruded tubes of a suitable resinous or plastic material (eg. thermoplastics such as polyethylene, vinyl or nylon, or thermosetting resins such as the phenolies, alkyd or epoxy resins, etc). The strings may also be made from tubes fabricated from a composition material including a quantity of an elastomer or natural rubber. The particular composition of the strings 10 depends to some extent on the nature of the items to be packed, and also upon the degree of protection required. In any event, it is essential that the individual segments 12 possess sufficient initial stiffness to provide both interlacing and support of the packed item. A degree of crushability or deformability is also essential so that shock will not be transmitted through the loose mass of strings to the packed item.

In the use of the packing material of the invention, a suitable carton Sit)A is first filled with a quantity of the strings 10 to provide a layer of adequate thickness to receive the item to be packed. Thereafter the item is positioned in the carton and the packing material positioned about the sides, within and on top of the item to insulate it from the walls 32 of the carton. Preferably the carton 30 is packed with a slight excess of material so thatthe mass of the strings 10 is pressure loaded to some extent upon sealing of the carton. The effect is to increase the interlocking provided by the wedge-shaped opening 16, and thereby increase the resistance of the jacking mass to migration of the article 22.

FIGURE 4 illustrates conditions as they might actually exist during shipment of the item, with the lines 34 indicating vibration of the carton on the oor 36 of a transporting vehicle. Under such conditions, resistance to aus?,

migration is continuously provided by the interlocking of the strings and by a certain amount of compacting and deforming of the cylindrical segments 12, as generally indicated at 38. Any sharp blows which might be transmitted to the carton will be absorbed by the mass due to its characteristic crushability orV deformability. This crushability is due in part to a breakdown of the initial stiffness ofthe cylindrical segments 12, and in part to a partial separation of the strings from one another due to a partial release of the interlocking Yor wedged contacts. It also results from the cylindrical shape of the individual segments 12, which allows air to be expelled from either end of the segment so that crushing may occur.

In carrying out the invention, I have found that the desired qualities Vof interlocking, crushability, and resistance to migration can be obtained with strings 10 having a length of from about 3 to 12 inches, and the diameter of the individual segments 12 ranging from about V16 to Mi inch. Preferably a length to diameter ratio of the segments should be within the range of about 4 to 1 to 8 to l; I have also found that strings composed of from three to about twenty of the segments 12 provide satisfactory results. If the length of the strings is substantially increased beyond the length indicated, the interlocking feature may Ibecome so great as` to prevent an easy handling of the packing material. Likewise, if the diameter of the segments 12 is substantially increased, or if the segments are excessively long in relation to diameter, an undesirable matting or self-packing of the packing material may occur. Optimum characteristics are those which will pro- Vvide the characteristic crushability of the packing mass and interlocking ofthe strings 10 to prevent migration.

From the above description, it will be evident that the present invention makes possible a very ecient packing of a wide variety of delicate items, and particularly very heavy items of electronic and opticalequipment, for eX- aniple, tubes, timers, meters, binoculars, lenses, and other such items. The invention is particularly useful with items of a delicate nature which may be renderedV useless because of change in position, alinement, or adjustment of the parts. Such changes can occur due to constant vibration of the'item against the wall of the container, without any visible breakage occurring. Since the present invention is efective in preventing the type of migration or movement of packed items which normally gives rise to this diificulty, it is much 4more effective than any similar packing material used heretofore.

I claim:

1. As an article of manufacture, a mass of packing material particularly adapted to providing maximum absorp- Vtion of shock-while preventing migration of relatively heavy packed articles therethrough, such mass of packing material having a multiplicity of partially interlocked elongated strings of hollow crushable cylinders, each ofV said strings comprising a hollow tube partially cut through at spaced apart intervals, such cut portions forming individual articulated tubular. segments having hinging relation at said cuts wherein the hingin-g provides wedgeshaped openings at said cuts and wherein each of the strings interlock with at least one of the other strings at said wedge-shaped openings, said interlocking y s rings extending throughout said mass, said packing material being capable of being positioned as a resilient, loose, substantially crushable mass within and around a packed item wherebyksaid mass prevents migration of said item.

2. An article as in claim 1 wherein each of said hollow tubes is an ordinary drinking straw cut in the manner indicated to form open hollow cylinders.

3. An article as in claim l wherein each of said hollow tubes is made of a plastic material. t

4. An article as in claim 1 wherein each of said hollow tubes is made of paper coated with a sizing material.

5. An article as in claim l wherein each of said hollow tubes is coated with an outer slip resistant material.`

6. As an article of manufacture, a shipping carton for frangible items, such carton being substantially completely iilled with a packing mass having a multiplicity of elongated strings of hollow crushable cylinders, each of Y i said strings being composed of a hollow tube partially cut through at spaced apart intervals, such cut portions forming individual Varticulated tubular segments having hinging relation at said cuts wherein the hing-ing provides wedgeshaped openings at said cuts and wherein each of the strings interlock with at least one of the other strings at said wedge-shaped openings, said interlocking strings extending throughout said mass whereby to prevent migrai tion of an article packed therein.

References Cited in the tile of this patent *Y 

